Fluidic Force Discrimination Assays: A New Technology for Tetrodotoxin Detection

Tetrodotoxin (TTX) is a low molecular weight (~319 Da) neurotoxin found in a number of animal species, including pufferfish. Protection from toxin tainted food stuffs requires rapid, sensitive, and specific diagnostic tests. An emerging technique for the detection of both proteins and nucleic acids is Fluidic Force Discrimination (FFD) assays. This simple and rapid method typically uses a sandwich immunoassay format labeled with micrometer-diameter beads and has the novel capability of removing nonspecifically attached beads under controlled, fluidic conditions. This technique allows for near real-time, multiplexed analysis at levels of detection that exceed many of the conventional transduction methods (e.g., ELISAs). In addition, the large linear dynamic range afforded by FFD should decrease the need to perform multiple sample dilutions, a common challenge for food testing. By applying FFD assays to an inhibition immunoassay platform specific for TTX and transduction via low magnification microscopy, levels of detection of ~15 ng/mL and linear dynamic ranges of 4 to 5 orders of magnitude were achieved. The results from these studies on the first small molecule FFD assay, along with the impact to detection of seafood toxins, will be discussed in this manuscript

Non-Traditional Vectors for Paralytic Shellfish Poisoning

Paralytic shellfish poisoning (PSP), due to saxitoxin and related compounds, typically results from the consumption of filter-feeding molluscan shellfish that concentrate toxins from marine dinoflagellates. In addition to these microalgal sources, saxitoxin and related compounds, referred to in this review as STXs, are also produced in freshwater cyanobacteria and have been associated with calcareous red macroalgae. STXs are transferred and bioaccumulate throughout aquatic food webs, and can be vectored to terrestrial biota, including humans. Fisheries closures and human intoxications due to STXs have been documented in several non-traditional (i.e. non-filter-feeding) vectors. These include, but are not limited to, marine gastropods, both carnivorous and grazing, crustacea, and fish that acquire STXs through toxin transfer. Often due to spatial, temporal, or a species disconnection from the primary source of STXs (bloom forming dinoflagellates), monitoring and management of such non-traditional PSP vectors has been challenging. A brief literature review is provided for filter feeding (traditional) and non-filter feeding (non-traditional) vectors of STXs with specific reference to human effects. We include several case studies pertaining to management actions to prevent PSP, as well as food poisoning incidents from STX(s) accumulation in non-traditional PSP vectors

The hearing of fitness to practice cases by the General Medical Council: Current trends and future research agendas

Over the last three decades a risk-based model of medical regulation has emerged in the United Kingdom. To promote a risk-averse operational culture of transparency and professional accountability the regulatory state has intervened in medical governance and introduced best-evidenced practice frameworks, audit and performance appraisal, Against this background the paper analyses descriptive statistical data pertaining to the General Medical Council’s management of the process by which fitness to practice complaints against doctors are dealt with from initial receipt through to subsequent investigative and adjudication stages. Statistical trends are outlined regarding complaint data in relation to a doctor’s gender and race and ethnicity. The data shows that there has been an increase in rehabilitative and/or punitive action against doctors. In light of its findings the paper considers what the long-term consequences may be, for both patients and doctors, of the increasing use of risk-averse administrative systems to reform medical regulation and ensure professional accountability

Definition of a consensus integrin adhesome and its dynamics during adhesion complex assembly and disassembly

Integrin receptor activation initiates the formation of integrin adhesion complexes (IACs) at the cell membrane that transduce adhesion-dependent signals to control a multitude of cellular functions. Proteomic analyses of isolated IACs have revealed an unanticipated molecular complexity; however, a global view of the consensus composition and dynamics of IACs is currently lacking. Here, we have integrated several IAC proteomes and generated a 2,412-protein integrin adhesome. Analysis of this dataset reveals the functional diversity of proteins in IACs and establishes a consensus adhesome of 60 proteins. The consensus adhesome likely represents a core cell adhesion machinery, centred around four axes comprising ILK-PINCH-kindlin, FAK-paxillin, talin-vinculin and α-actinin-zyxin-VASP, and includes underappreciated IAC components such as Rsu-1 and caldesmon. Proteomic quantification of IAC assembly and disassembly detailed the compositional dynamics of the core cell adhesion machinery. The definition of this consensus view of integrin adhesome components provides a resource for the research community

Ecophysiology and optical detection of harmful algal blooms

Harmful algal blooms (HABs) adversely impact public and ecosystem health, the economy, seafood industry, and recreation. Examples of destruction include physical damage to other organisms, nutrient and oxygen depletion from the water, and the production of potent toxins, among other deleterious impacts. There are numerous harmful and/or toxic algal species, each with its own bloom dynamics and ecological controls. The purpose of this dissertation was to evaluate HAB physiology, ecology, and optical properties in order to understand the factors responsible for blooms and toxicity and to improve detection capabilities. ^ The physiology of Alexandrium, the toxic dinoflagellate responsible for paralytic shellfish poisoning (PSP), was examined in response to a range of environmental conditions. In particular, the effects of temperature, growth irradiance, and salinity on Alexandrium growth rates and toxin composition were determined. Alexandrium was also investigated as a possible source of PSP toxins found in abalone off the coast of South Africa. ^ Two HAB case studies provided information on bloom ecology. Alexandrium blooms in the Gulf of Maine were studied to assess the relationship between HAB physiology and ecology. Brown tides in Long Island embayments were also investigated to determine the role of ecology in bloom formation and the capability for optical detection of ecological processes. ^ The optical properties of several bloom-forming species were examined to determine what leads to the distinct ocean colors often associated with blooms, and existing bio-optical methods were evaluated under extreme algal bloom conditions. Additionally, the variability in Alexandrium optical properties as a function of environmental conditions was quantified to identify characteristics that may serve as diagnostics for physiological responses. Results demonstrated how optical techniques could be used to detect blooms and interpret physiological and ecological characteristics. ^ Thus, each chapter in this dissertation addresses the interconnections between HAB physiology, ecology, and optical properties. Specific significant results of this research include improved capabilities for predicting PSP events based on environmental conditions, novel toxin transference through the food web, determination of factors that lead to brown tide initiations, and improved understanding of optical methods that apply to extreme algal blooms.

Cyanobacterial Harmful Algal Blooms: Chapter 15: Cyanotoxins Workgroup Report

The Cyanotoxins Workgroup was charged with the identification and prioritization of research needs associated with: the identification of cyanotoxins; toxicokinetics and toxicodynamics of cyanotoxins; human susceptibility to the toxins; cyanobacterial genetics/omics and factors for inclusion in predictive models of toxin production; and risk reduction from an intentional or accidental release of cyanotoxins. Papers presented for the Cyanotoxins Session of the symposium on toxin types, toxicokinetics, and toxicodyamics (See Humpage this volume), cyanobacterial genetics of toxin production (See Neilan this volume), and parameters related to human risks from cyanobacterial exposure (See Love this volume) set the stage for Cyanotoxins Workgroup discussions. A consensus was achieved regarding the need to focus on the major identified classes of cyanotoxins. The group expressed the belief that the most significant toxic components of presently occurring harmful algal blooms have been identified, and the knowledge gaps for these most prevalent toxins are great enough to warrant the attention of most of our future research. This belief does not negate the need to study mixtures of cyanotoxins and toxin precursors, especially those most likely to occur within a given bloom. Moreover, there is also a significant likelihood that novel cyanobacterial blooms and toxins will continue to emerge, and future identification of unknown bloom-forming species and their toxins will require ongoing diligence